• Corrosion Science and Technology
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• 제8권1호
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• pp.11-14
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• 2009

The osmotic blistering behavior of polymeric coating film which is in contact with an aqueous environment has been investigated. In this study, the coating film has been assumed to be linearly viscoelastic. Interfacial stresses induced in a laminate model consisting of the viscoelastic film and the elastic substrate as the film absorbs moisture from the ambient environment have been investigated using the time-domain boundary element method. The overall stress intensity factor for interfacial cracks subjected to a uniform osmotic pressure has been computed using the tractions at the crack tip node. The magnitude of stress intensity factors decreases with time due to viscoelastic relaxation, but remains constant at large times.

• Journal of Mechanical Science and Technology
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• 제18권1호
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• pp.12-19
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• 2004

Using LSM (laser scanning method) , the radius of curvature due to thermal deformation in polyimide film coated on Si substrate is measured. Since the polyimide film shows viscoelastic behavior, i.e., the modulus and deformation of the film vary with time and temperature, we estimate the relaxation modulus and the residual stresses of the polyimide film by measuring the radius of curvature and subsequently by performing viscoelastic analysis. The residual stresses relax by an amount of 10％ at 100$^{\circ}C$ and 20% at 150$^{\circ}C$ for two hours.

• 대한기계학회논문집A
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• 제24권3호
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• pp.685-690
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• 2000

This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate as the film absorbs moisture from the ambient environment. Th e time domain boundary element method is employed to investigate the behavior of interface stresses. The order of the free-edge singularity is obtained numerically for a given viscoelastic model. It is shown that the stress singularity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model considered.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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• pp.437-443
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• 1999

This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate subjected to uniform temperature change. The viscoelastic film has been assumed to be thermorheologically simple. The time-domain boundary element method(BEM) has been employed to investigate the behavior of interface stresses. The order of the free-edge singularity has been obtained numerically for a given viscoelastic model. It is shown that the free-edge stress intensity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model considered.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.19-26
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• 1999

This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate as the film absorbs moisture from the ambient environment. The rime-domain boundary element method is employed to investigate the behavior of interface stresses. The order of the free-edge singularity is obtained numerically for a given viscoelastic model. It is shown that the free-edge stress intensity factor is relaxed with time,'while the order of the singularity increases with time for the viscoelastic model considered.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.389-394
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• 2003

In this study, the stress singularity factors generated during cooling down from high curing temperature to room temperature have been analyzed for the viscoelastic thin film. The time domain boundary element method has been employed to investigate the behavior of stresses for the whole interface. Within the context of a linear viscoelastic theory, a stress singularity exists at the point where the interface between the elastic substrate and the viscoelastic thin film intersects the free surface.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 추계기술심포지움논문집
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• pp.137-142
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• 2002

This paper deals with the stress singularity induced at the interface corner between the elastic substrate and the viscoelastic thin film as the polymeric film absorbs moisture from the ambient environment. The boundary element method is employed to investigate the behavior of Interface stresses. The order of the singularity is obtained numerically for a given viscoelastic model. It is shown that the stress singularity factor is relaxed with time, while the order of the singularity increases with time for the viscoelastic model considered.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2003년도 추계학술대회 발표 논문집
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• pp.146-153
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• 2003

This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate subjected to the combined influence of temperature change and moisture absorption. A boundary element analysis is employed to investigate the behavior of interface stresses. The film is assumed to be thermorheologically simple. It is further assumed that moisture effects are analogous to thermal effects. Numerical results are presented for a given viscoelastic model, indicating the singular residual stresses induced during cooling down from the curing temperature, and how they can be altered by subsequent moisture absorption at room temperature.

• 마이크로전자및패키징학회지
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• 제10권1호
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• pp.25-29
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• 2003

이 논문은 고분자 박막이 주변으로부터 수분을 흡수하게 될 때, 탄성 기판과 점탄성 박막의 계면 모서리에서 발생하는 응력 특이성을 다루고 있다. 계면에서 발생하는 응력을 조사하기 위해서 경계 요소법이 사용되고 있다. 주어진 점탄성 모델에 대해서 특이 차수가 수치적으로 계산된다. 이 논문에서 고려하고 있는 점탄성 모델에 대해서, 응력특이계수는 시간이 경과함에 따라 이완되고 있으나 특이 차수는 증가되고 있음을 보여준다.

• 한국응용과학기술학회지
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• 제18권4호
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• pp.261-272
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• 2001

An ACR/HMMM film was prepared by blending high-solid ACR with curing agent, hexamethoxymethyl melamine (HMMM). An active curing reaction was observed at $170^{\circ}C$. The dynamic viscoelastic $T_{g}$ of the final film increased with the static viscoelastic $T_{g}$ of the film. The log damp value, which means a viscoelastic ratio, decreased with the increase in the curing temperature of the film. Physical properties of the films were within a suitable range for films, and by an accelerated weathering resistance test the films were proved weather resistible ones.